The existing melamine foam is low-density and high-open-ratio flame-retardant foam, has excellent flame retardant, sound absorption, thermal insulation and cleaning functions, and can be widely applied to the construction, transportation, household and industry fields. In practical applications, some fields, such as cushion, sofa, thermal insulation, cleaning and other fields, make higher requirements for the density and strength of melamine foam, but the density of the melamine foam on the current market is generally 4 to 10 kg/m3, which is difficult to meet the requirements, thereby limiting the application fields of the melamine foam. Therefore, one important direction of research on the melamine foam is to improve the density and strength of the melamine foam.
Some reports on technologies related to the production of the melamine foam have been made at home and abroad, but rarely involve the preparing method of high-density melamine foam. For example, the invention patent with a Patent No., “ZL 200510087184.0” discloses a production method of a high-solid-content melamine resin, wherein the melamine resin is used for producing melamine foam plastics, the molar ratio of formaldehyde to melamine in the used raw materials is 2:1 to 4:1, and the solid content is 60% to 90%; the invention patent with a Patent No. “ZL 201210128145.0” discloses a preparing method of melamine formaldehyde resin for foam, the molar ratio of formaldehyde to melamine in the used raw materials is 1:1 to 4:1, the solid content is 40% to 80%, and a buffer and a stabilizer are introduced to solve the resin synthesis and stability problems. The above-mentioned patent technology proposes the preparing method of melamine foam, but the density and strength are still difficult to adapt to the higher requirements.